Corrosion resistant composition



' iii c 2,799,652 l Patented July 16, 1957 Conn sioN nEsisrANTCOMPOSITION Ellis K. Fields, Chicago, 13., assiguor to Standard OilCompany, Chicago, 50., a corporation of lndiana No Drawing. ApplicationJune 17, 1953, Serial No. 362,427

17 Claims. (Cl. 25232.7)

This invention relates to improvedi compositions which are effectivecorrosion inhibitors and which are non-corrosive to silver, silveralloys and similar metals. More particularly, the invention pertains tolubricant compositions which are non-corrosive to such metals andinhibit the corrosion thereof by sulfur and/or corrosivesulfurcontaining compounds.

Advances in the design and construction of internal combustion enginesaimed at increased efficiency and economy have led to lubricationproblems. To meet the increased severe demands upon engines, many typesof lubricant additives have been developed to obtain certain desiredcharacteristics. Among the more effective addition agents which havebeen developed for compounding with lubricants are manysulfur-containing organic compounds, such as sulfurized terpenes,sulfurized hydrocarbon oils, vegetable oils or animal oils, xanthateesters, organic polysulfides, particularly polyalkyl polysulfides, metalsalts of organo-substituted thioacids of phosphorus, metal salts of thereaction product of a phosphorus sulfide and a hydrocarbon, such as forexample, polybutenes and other polyolefins, and combinations of theforegoing.

Recent increased use of silver and similar metals in the construction ofimproved internal combustion engines has created new problems in the useof sulfur-containing additives in lubricants for such engines; theprimary problem created being the corrosion of such silver parts of theengine by the sulfuncontaining additives. While such corrosion can beeliminated by avoiding the use of sulfurcontaining additives inlubricants for such engines, this solution of the problem is accompaniedby the loss of the highly desired beneficial effects of the additives ofthis type.

It is an object of the present invention to provide a non-corrosivecomposition. Another object of the invention is to provide a compositionnon-corrosive to silver and similar metals. A still further object ofthe invention is to provide a composition which will inhibit thecorrosion of silver and similar metals by sulfur and/ or organicsulfur-containing compounds. A still further object of the invention isto provide a lubricant composition which is non-corrosive. Still anotherobject of the invention is to provide a lubricant composition containingan addition agent which will inhibit the corrosion of silver and similarmetals by sulfur and/ or organic sulfur-containing compounds. A furtherobject of the invention is to provide a method of inhibiting thecorrosion of silver and similar metals. Still another object of theinvention is to provide a method of lubricating internal combustionengines containing silver and similar metal parts, and inhibiting thecorrosion of such metals by lubricants which contain sulfur and/ororganic sulfur-containing compounds.

In accordance with the present invention, the foregoing objects can beattained by employing in oleaginous materials from about 0.02% to aboutand preferably from about 0.25% to about 5 of the oil-soluble productobtained by reacting 2,5-dimercapto-1,3,4-thiadiazole with anunsaturated ketone in the molar ratio of from 1:2 to 4:1. The reactionis carried out by heating the mixture of the thiadiazole and unsaturatedketone at a temperature of from about 40 C. to about 140 C. for a periodof 0.5 hour to about 16 hours. To facilitate the reaction a solvent suchas dioxane, Cellosolve, ethylene glycol, ethyl ether, etc, can be used.

The ketone can be an aliphatic, aromatic or heterocyclic unsaturatedketone containing from about 4 to about 40 carbons and from 1 to 6double bonds. Mixtures of such unsaturated ketones can also be used.Examples of such ketoues are mesityl oxide, phorone, isophorone, benzalacetophenone, furfural acetone, difurfural acetone, butylidene methylethyl ketones, etc.

The following examples are illustrative of the preparation of the abovereferred to reaction products:

EXAMPLE I A solution of 41.0 grams (0.2 mole) benzal acetophenone and 15grams (0.1 mole) 2,5-dimercapto-l,3,4- thiadiazole in 50 cc. dioxane wasrefluxed for 5 hours and the mixture then cooled. The cooled mixture waspoured into Water, the lower layer taken up in benzene, washed withwater and dried. The dried solution was filtered and the filtrate freedof benzene by evaporation. A dark viscous product having a sulfurcontent of 15.3%, a nitrogen content of 4.38%, a carbon content of 69.5%and a hydrogen content of 4.89% was recovered.

EXAMPLE H A mixture of 30 grams (.2 mole) 2,5-dimercapto-l,3,4-thiadiazole and 55 cc. (.44 mole) mesityl oxide was heated at -90 C. for6 hours and the resultant clear dark solution stripped in vacuo. Therecovered product had a sulfur content of 37.6% and a nitrogen contentof 10.8%;

The above-described reaction products can be used in amounts of fromabout 0.02% to about 10%, and preferably from about 0.25% to about 5%,in combination with lubricant base oils, such as hydrocarbon oils,synthetic hydrocarbon oils, such as those obtained by the polymerizationof hydrocarbons, such as olefin polymers; synthetic lubricating oils ofthe alkylene-oxide type, for example, the Ucon oils, marketed by Carbideand Carbon Corporation, as well as other synthetic oils, such as thepolycarboxylic acid ester-type oils, such as the esters of adipic acid,sebacic acid, maleic acid, azelaic acid, etc.

While the above-described reaction products can be suitably employedalone in combination with a base oil, they are usually used incombination with other lubricant addition agents which impart variousdesired characteristics to the base oil. Usually, these reactionproducts are used in conjunction with detergent-type additives,particularly those which contain sulfur and/ or phosphorus and sulfur.Additives of this type are usually used in amounts of from about 0.002%to about 10%, and preferably from about 0.01% to about 5%. Among thephosphorusand sulfur-containing addition agents are the neutralizedreaction products of a phosphorus sulfide and a hydrocarbon, an alcoholand a ketone, an amine or an ester. Of the phosphorus sulfide reactionproduct additives, the neutralized reaction products of a phosphorussulfide, such as a phosphorus pentasulfide, and a hydrocarbon of thetype described in U. S. 2,316,082, issued to C. M. Loane et al. April 6,1943, are preferred. As taught in this patent, the preferred hydrocarbonconstituent of the reaction is a mono-olefin hydrocarbon polymerresulting from the polymerization of low molecular weight mono-olefinhydrocarbons, such as propylene, butenes, amylenes or copolymersthereof. Such polymers may be obtained by the polymerization ofmonoolefins of less than 6 carbon atoms in the presence of a catalyst,such as sulfuric acid, phosphoric acid, boron fluoride, aluminumchloride or other similar halide catalysts of the Friedel-Crafts type.

The polymers employed are preferably mono-olefin polymers or mixtures ofmono-olefin polymers and isomono-olefin polymers having molecularweights ranging from about 150 to about 50,000 or more, and preferablyfrom about 500 to about 10,000. Such polymers can be obtained, forexample, by the polymerization in the liquid phase of a hydrocarbonmixture containing monoand isomono-olefins, such as butylene andiso-butylene at a temperature of from about 80 F. to about 100 F. in thepresence of a metal halide catalyst of the Friedel- Crafts type, such asfor example, boron fluoride, aluminum chloride, and the like. In thepreparation of these polymers a hydrocarbon mixture containingiso-hutylene, butylenes and butanes recovered from petroleum gases,especially those gases produced in the cracking of petroleum oils in themanufacture of gasoline can be used.

Another suitable polymer is that obtained by polymerizing, in the liquidphase, a hydrocarbon mixture comprising substantially C3 hydrocarbons inthe presence of an aluminum chloride-complex catalyst. The catalyst ispreferably prepared by heating aluminum chloride with isooctane. Thehydrocarbon mixture is introduced into the bottom of the reactor andpassed upwardly through the catalyst layer, while a temperature of fromabout 50 F. to about 110 F. is maintained in the reactor. The propaneand other saturated gases pass through the catalyst while the propyleneis polymerized under these conditions. The propylene polymer can befractionated to any desired molecular weight, preferably from about 500to about 1000, or higher.

Other suitable polymers are those obtained by polymerizing a hydrocarbonmixture containing about to about 25% isobutylene at a temperature offrom about 0 F. to about 100 F., and preferably 0 F. to about 32 F. inthe presence of boron fluoride. After the polymerization of theisobutylene, together with a relatively minor amount of the normalolefins present, the reaction mass is neutralized, washed free of acidicsubstances, and the unreacted hydrocarbons subsequently separated fromthe polymers by distillation. The polymer mixture so obtained, dependingupon the temperature of reaction, varies in consistency from a lightliquid to viscous oily material and contains polymers having molecularweights ranging from about 100 to about 2000, or higher. The polymers soobtained may be used as such or the polymers may be fractionated underreduced pressure into fractions of increasing molecular weights andsuitable fractions obtained reacted with the phosphorus sulfide toobtain the desired reaction products. The bottoms resulting from thefractionation of the polymer which have Saybolt Universal viscosities at210 F. ranging from I about 50 seconds to about 10,000 seconds are wellsuited for this purpose.

Essentially parafiinic hydrocarbons, such as bright stock residuums,lubricating oil distillates, petrolatums, or parafiin Waxes, may beused. There can also be employed the condensation products of any of theforegoing hydrocarbons, usually through first halogenating thehydrocarbons and reacting with aromatic hydrocarbons in the presence ofanhydrous inorganic halides, such as aluminum chloride, zinc chloride,boron fluoride, and the like.

Examples of other high molecular weight olefinic hydrocarbons which canbe employed are cetene (C16), cerotene (C26), melene (C30) and mixedhigh molecular weight alkenes obtained by cracking petroleum oils.

Other preferred olefins suitable for the preparation of the phosphorussulfide reaction products are olefins having at least 20 carbon atoms inthe molecule of which from about 13 carbon atoms to about 18 carbonatoms, and preferably at least 15 carbon atoms, are in a long chain.Such olefins can be obtained by the dehydrogenation of alkyl halides,preferably long chain alkyl halides, particularly halogenated parafiinwaxes.

As a starting material there can be used the polymer or syntheticlubricating oil obtained by polymerizing unsaturated hydrocarbonsresulting from the vapor phase cracking of paraifin waxes in thepresence of aluminum chloride which is fully described in U. S. Patents1,955,- 260; 1,970,402 and 2,091,398. Still another type of olefinpolymer which may be employed is the polymer resulting from thetreatment of vapor phase cracked gasoline and/ or gasoline fractionswith sulfuric acid or solid adsorbents, such as fullers earth, wherebyunsaturated polymerized hydrocarbons are removed. The reaction productsof the phosphorus sulfide and the polymers resulting from thevolatilization of hydrocarbons as described, for example, in U. S.Patents 2,197,768 and 2,191,787 are also suitable.

Other hydrocarbons that can be reacted with a phosphorus sulfide arearomatic hydrocarbons, such as for example, benzene, naphthalene,toluene, xylene, diphenyl and the like, or an alkylated aromatichydrocarbon, such as for example, benzene having an alkyl substituenthaving at least 4 carbon atoms, and preferably at least 8 carbon atoms,such as a long chain paraflin wax.

The phosphorus sulfide-hydrocarbon reaction product can be readilyobtained by reacting a phosphorus sulfide, for example, P255 with thehydrocarbon at a temperature of from about 200 F. to about 500 17., andpreferably from about 200 F. to about 400 F., using from about 1% toabout and preferably from about 5% to about 25% of the phosphorussulfide in the reaction. it is advantageous to maintain a non-oxidizingatmosphere, such as for example, an atmosphere of nitrogen above thereaction mixture. Usually, it is preferable to use an amount of thephosphorus sulfide that will completely react with the hydrocarbon sothat no further purification becomes necessary; however, an excessamount of phosphorus sulfide can be used and separated from the productby filtration or by dilution with a hydrocarbon solvent, such as hexane,filtering and subsequently removing the solvent by suitable means, suchas by distillation. If desired, the reaction product can be furthertreated with steam at an elevated temperature of from about 100 F. toabout 600 F.

The phosphorus sulfide-hydrocarbon reaction product normally shows atitratable acidity which is neutralized by treatment with a basicreagent. The phosphorus sultide-hydrocarbon reaction product whenneutralized with a basic reagent containing a metal constituent ischaracterized by the presence or retention of the metal constituent ofthe basic reagent.

The neutralized phosphorus sulfide-hydrocarbon reaction product can beobtained by treating the acidic reaction product with a suitable basiccompound, such as hydroxide, carbonate, oxide or sulfide of an alkalineearth metal or an alkali metal, such as for example, potassiumhydroxide, sodium hydroxide, sodium sulfide, calcium oxide, lime, bariumhydroxide, barium oxide, etc. Other basic reagents can be used, such asfor example, ammonia or an alkylor aryl-substituted ammonia, such asamines. The neutralization of the phosphorus sulfide-hydrocarbonreaction product is carried outpreferably in a nonoxidizing atmosphereby contacting the acidic reaction product either as such or dissolved ina suitable solvent, such as naphtha, with a solution of the basic agent.As an alternative method the reaction product can be treated with solidalkaline compounds, such as KOH, NaOH, Na2CO3, KzCOs, CaO, BaO, Ba(OH)2,NazS, and the like, at an elevated temperature of from about F. to about600 F. Neutralized reaction products containing a heavy metalconstituent, such as for example, tin, titanium, aluminum, chromium,cobalt, zinc, iron, and the like, can be obtained by reacting a salt ofthe desired heavy metal with the phosphorus sulfide-hydrocarbon reactionproduct which has been treated with a basic reagent such asabove-described.

Other phosphorus sulfide reaction products which can be used are thereaction products of a phosphorus sulfide and a fatty acid ester of thetype described in U. S. 2,399,243; the phosphorus sulfide-degrasreaction products of U. S. 2,413,322; the reaction product of analkylated phenol with the condensation product of P285 and turpentine ofU. S. 2,409,877 and U. S. 2,409,878; the reaction product of aphosphorus sulfide and stearonitrile of U. 5. 2,416,807, etc.

The silver corrosion inhibiting property of the abovedescribedthiadiazole reaction products is demonstrated by the data in Table I,which were obtained by subjecting mixtures of a hydrocarbon oil, aneutralized reaction product of P285 and a polybutene, and theabovedescribed 2,5-dimercapto-1,3,4-thiadiazole reaction products to thefollowing test, hereinafter referred to as the modified EMD test:

A silver strip 2 cm. x 5.5 cm. with a small hole at one end forsuspension is lightly abraded with No. steel wool, wiped free of anyadhering steel wool, washed with carbon tetrachloride, air-dried andthen Weighed to 0.1 milligram. 300 cc. of the oil to be tested is placedin a 500 cc. lipless glass beaker and the oil heated to a temperature of300 F. (i-2 F.) and the silver strip suspended in the oil so that thestrip is completely immersed therein. The oil in the beaker is stirredby means of a glass stirrer operating at 300 R. P. M. At the end oftwenty-four hours the silver test strip is removed and while still hotrinsed thoroughly with carbon tetrachloride and air-dried. Theappearance of the strip is then visually noted and given ratingsaccording to the following scale:

1Bright 2Stained 3Grey-Black 4Black, Smooth 5Black, Flake Table 1 SilverCorrosion Sample Wt. Loss in mg.

Visual Rating Since a weight loss of no more than 20 milligrams isdesirable, the ability of the 2,5-dimercapto-1,3,4-thiadiazole-ketonereaction product of this invention to inhibit silver'corrosion isdemonstrated by the above data.

The eifectiveness of the herein-described thiadiazole reaction productsin inhibiting corrosion toward copper and/ or lead-containing metals,such as for example, copper-lead alloys, is demonstrated by the data inTable II, obtained by subjecting the above samples to the followingtest:

A cooper-lead test specimen is lightly abraded with steel wool, washedwith naphtha,'dri'ed and weighed to the nearest milligram. The cleanedcopper-lead test specimen is suspended in a steel beaker, cleaned with ahot tri-sodium phosphate solution, rinsed with water, acetone and dried,and 250' grams of the oil to be tested, together with 0.625 gram leadoxide and 50 grams of a 30-35 mesh sand charged to the beaker. Thebeaker is then placed in a bath or heating block and heated to atemperature of 300 F. (i2 F.) while the contents are stirred by means ofa stirrer rotating at 750 R. P. M. The contents of the beaker aremaintained at this tempera ture for twenty-four hours, after which thecopper-lead test specimen is removed, rinsed with naphtha, dried andweighed. The test sepcimen is then replaced in the beaker and anadditional 0.375 gram of lead oxide added to the test oil. At the end ofan additional twenty-four hours of test operation the test specimen isagain removed, rinsed and dried as before, and weighed. The testspecimen is again placed in the beaker, together with an additional0.250 grams of lead oxide, and the test continued for anothertwenty-four hours (seventy-two hours total). At the conclusion of thistime the test specimen is removed from the beaker, rinsed in naphtha,dried and weighed.

The loss in weight of the test specimen is recorded after each Weighing.

This test, known as the Stirring Sand Corrosion Test, is referred tohereinafter as S. S. C. T.

Since weight losses of no more than 200 milligrams in 48 hours and 500milligrams in 72 hours are desirable, the copper-lead corrosiveinhibiting property of the herein-described2,5-dimercapto-1,3,4-thiadiazole derivatives is clearly demonstrated bythe above data.

Under certain conditions it is desirable to use in lubricantcompositions elemental sulfur or an organic sulfurcontaining compound ofthe type hereinabove described either alone or in combination with otheradditives. Effective lubricant compositions are obtained by thecombination of the neutralized reaction products of a phosphorus sulfideand a hydrocarbon, as above described, with elemental sulfur, or anorganic sulfur-containing compound, such as sulfurized mineral oils,sulfurized nondrying animal and vegetable oils, sulfurized olefins andolefin polymers, sulfurized sperm oil, etc., as described and claimed inU. S. Reissue 22,464, issued to C. D. Kelso et al., April 4, 1944, orwith sulfurized terpenes, for example, dipentene, as described andclaimed in U. S. 2,422,585, issued to T. H. Rogers et al., June 17,1947. While these compounds impart highly desired characteristics tolubricants and effectively inhibit the corrosion of copper and/or lead,they are under certain conditions corrosive to silver and similarmetals, and for this reason, lubricants containing such addition agentsat times fail to pass the above-described EMD test. In accordance withthe present invention, however, the incorporation in such lubricantcompositions of small amounts, namely, from about 0.1% to about 10%, andpreferably from about 0.25% to about 5% of the herein-described2,5-dimercapto-l,3,4-thiadiazole reaction products effectively inhibitsthe corrosiveness of the silver corrosive compounds without impairingtheir other desired properties.

The ability of the herein-described 2,5-dimercapto- 1,3,4-thiadiazolederivatives to inhibit the silver corrosion tendency of activesulfur-containing organic compounds is demonstrated by. the followingEMD data in Table III, obtained with the following compositions:

Sample A .-Control (solvent-extracted SAE-30 mineral oil +33%barium-containing neutralized reaction product of P28 and a polybuteneof about 1000 molecular weight +0.75% sulfurized dipentene).

Sample B .--A .+0.15% product of Example .I.

As noted with respect to the data in Table I, supra, a weight loss ofless than 20 is desirable.

Although the invention has been described in connection with the use ofthe'herein-described 2,5-dimercapto- 1,3,4-thiadiazole derivatives incombination with the one or more secondary additives in lubricantcompositions,

the invention'is not restricted to such use, since these derivativesfind utility when used alone in various lubri-. cant compositions orhydrocarbon oil compositions to impartimproved and desiredcharacteristics thereto. Thus, for example, these derivatives may beused alone in hydrocarbon oils of high sulfur crudes to inhibit thecorrosion of such oils to silver or copper and/or lead-containingmetals, and to efiectively inhibit the oxidation of hydrocarbon oils.

While this invention has been described in connection with the use ofthe herein-described additives and lubricant compositions, their use isnot limited thereto; but the same can be used in products other thanlubricating oils, such as for example, fuel oils, insulatingoils,greases, non-drying animal andvegetable oils, waves, asphalts, and anyfuels for internal combustion engines, particularly where sulfurcorrosion must be combatted.

Concentrates of a suitable oil base containing more than for example, upto 50% or more of the herein-described thiadiazole derivatives, alone orin combination with more than 10% of other additives, such asdetergent-type additives, can be used for blending with hydrocarbon oilsor other oils in the proportions desired for the particular conditionsof use to give a finished product containing from about 0.02% to about10% of the 2,5-dimercapto-1,3,4 thiadiazole-unsaturated ketone reactionproduct.

Percentages given herein and in the appended claims are weightpercentages unless otherwise stated.

Although the present invention has been described with reference tospecific preferred embodiments thereof, the invention is not to beconsidered as limited thereto but includes within its scope suchmodifications and variations as come within the spirit of the appendedclaims.

I claim:

1. A lubricant composition comprising a major proportion of anoleaginous material containing a compound normally corrosive to silverselected from the group consisting of. elemental sulfur, asulfur-containing organic compound and mixtures thereof and from about0.02% to about 10% of an oil-soluble reaction product of 2,5-dimercapto-1,3,4-thiadiazole, and an unsaturated ketone having at leastone olefinic double bond, and from about 4 to about 40 carbon atomsselected from the class consisting of an unsaturated aliphatic ketoneand an unsaturated aromatic ketone. said reaction product being obtainedby reacting said thiadiazole and said ketone in the molar ratio of from1:2 to 4:1, respectively, at a temperature of from about 40 C. to about140 C.

2. A composition as described in claim 1 in which the unsaturated ketoneis an aliphatic unsaturated ketone.

3. A composition as described in claim 1 in which the unsaturated ketoneis an aromatic unsaturated lretone.

'4. A composition as described in claim 2 in which the ketone is mesityloxide.

5. A composition as described in claim 3 in which the ketone is benzalacetophenone.

6. A lubricantcomposition comprising a major proportionof an olcaginousmaterial, from. about 0.001% to about 10% of a compound normallycorrosive to silver selected from the group consisting of elementalsulfur, a

- sulfur'containing organic compound and mixtures thereof,

and from about 0.02% to about 10% of an oil-soluble reaction product of2,5-dimercapto1,3,4-thiadiazole and an unsaturated ketone having atleast one olefinic double bond, and from about 4to about 40 carbon atomsse lected from the class consisting of an unsaturated aliphaticketoneand an unsaturated aromatic ketone, said reaction product being obtainedby reacting said thiadiazole and said lretone in the molar ratio of from1:2 to 4: 1, respectively, at a temperature of from about 40 C. to aboutC.

7. A lubricant composition comprising a major proportion of alubricating oil, from about0.00l% to about 10% of a phosphorusandsulfur-containing detergenttype additive, and from about 0.02% to about10% of an GilrSOIllblfi reaction product of 2,5-dimercapto-1,3,4thiadiazole and an unsaturated ketone having at least one olefinicdouble bond, and from about 4 to about 40 carbon atoms selected from theclass consisting of an unsaturated aliphatic ketone and an unsaturatedaromatic ketone, said reaction product being obtained by reacting saidthiadiazole and said ketone inthe molar ratio of from 1:2 to 4:1,respectively, at a temperature of from about 40 C. to about 140 C.

which the unsaturated ketone is an aliphaticunsaturated ketone.

9. A lubricant composition as described in claim 7 in which theunsaturated ketone is an aromaticunsaturated ketone.

10. A lubricant composition as described in claim 7 in which thedetergent-type additive is a neutralized reaction product of aphosphorus sulfide and a hydrocarbon.

11. A lubricant composition as described in claim 7 in which thedetergent-type additive is an alkaline earth metal-containing reactionproduct of a phosphorus sulfide and a hydrocarbon.

12. A lubricant composition as described in claim 7 in which thedetergent-type additive is a barium-containing neutralized reactionproduct of a phosphorus sulfide and an olefin polymer.

13. A lubricant composition as described in claim 7 in which thedetergent-type additive is an alkali metalcontaining reaction product ofa phosphorus sulfide and a hydrocarbon.

14. A lubricant composition as described in claim 8 in which the ketoneis mesityl oxide.

15. A lubricant composition as described in claim 9 in which the ketoneis benzal acetophenone.

16. An addition agent for lubricant compositions containing a compoundnormally corrosive to silver selected from the group consisting ofelemental sulfur, a sulfurcontaining organic compound and mixturesthereof, comprising a concentrated solution of a hydrocarbon oilcontaining more than 10% of an oil-soluble reaction product obtained byreacting 2,5-dimercapto-1,3,4-thiadiazole and an unsaturated ketonehaving at least one olefinic double bond selected from the classconsisting of an unsaturated aliphatic ketone and an unsaturatedaromatic ketone in the molar ratio of from 1:2 to 4:1 respectively, at atemperature of from about 40 C. to about 140 C., said solution beingcapable of dilution with a hydrocarbon oil containing a compoundnormally corrosive to silver selected from the group consisting ofelemental sulfur, a

uct of 2,S-dimercapto-1,3,4-thiadiazo1e and an unsaturated 10 ketonehaving at least one olefinic double bond, and from about 4 to about 40carbon atoms selected from the class consisting of an unsaturatedaliphatic ketone and an unsaturated aromatic ketone, said reactionproduct being obtained by reacting said thiadiazole and said ketone inthe molar ratio of from 1:2 to 4:1, respectively, at a temperature offrom about 40 C. to about 140 C.

No references cited.

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTION OF ANOLEAGINOUS MATERIAL CONTAINING A COMPOUND NORMALLY CORROSIVE TO SILVERSELECTED FROM THE GROUP CONSISTING OF ELEMENTAL SULFUR, ASULFUR-CONTAINING ORGANIC COMPOUND AND MIXTURES THEREOF AND FROM ABOUT0.02% TO ABOUT 10% OF AN OIL-SOLUBLE REACTION PRODUCT OF2,5DIMERCAPTO-1,3,4-THIADIAZOLE, AND AN UNSATURATED KETONE HAVING ATLEAST ONE OLEFINIC DOUBLE BOND, AND FROM ABOUT 4 TO ABOUT 40 CARBONATOMS SELECTED FROM THE CLASS CONSISTING OF AN UNSATURATED ALIPHATICKETONE AND AN UNSATURATED AROMATIC KETONE, SAID REACTION PRODUCT BEINGOBTAINED BY REACTING SAID THIADIAZOLE AND SAID KETONE IN THE MOLAR RATIOOF FROM 1:2 TO 4:1, RESPECTIVELY, AT A TEMPERATURE OF FROM ABOUT 40*C.TO ABOUT 140*C.